Helical spring coiling device



Feb. 13, 1934. w. H. MOON HELICAL SPRING COILING DEVICE Filed April 9,1932 INVENTOR. W/u/flrr M00! BY KM f M Z0 ATTORNEYJ.

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Patented Feb. 13, 1934 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to a device for coiling helical springs. The saiddevice is particularly useful as an attachment for a bed spring weavingmachine but is equally useful in winding helical springs for other uses.

Inthe manufacture of woven bed springs, it is important that the helicalcoils which make up the spring be made with extremely accurate pitch anddiameter since each spring must be woven into mesh with adjacentsprings. If succeeding coils are not wound with substantially the samepitch, it is impossible for each turn of a coil to be fed intoengagement with the corresponding turn of the preceding coil. This isparticularly important where the coiling and weaving devices are part ofa single machine, the coils being fed from the coiling device directlyinto engagement with the preceding coils without manual guidance.However, it is also of great importance where the coiling and weavingare done at two different operations. The accuracy of pitch must bemaintained in the latter case as well as in the former. The presentinvention has for its object the production of a device which windsrelatively long helical springs with an accuracy of pitch and diameterheretofore impossible.

The principal feature of the invention by which this result isaccomplished resides in the provision of a relatively stationary mandrelabout which is placed a rotating sleeve. The spring wire is fed betweenthe sleeve and the mandrel and is bent about the mandrel by thefrictional engagement of the wire with the'internal surface of thesleeve. A relatively large number of coils are maintained between themandrel and sleeve surfaces so that the frictional action of the sleeveupon the wire is maintained for a suflicient time to remove all tendencyfor the spring to change form when it is released from the mandrel.

Another feature of the invention resides in the provision in the outersurface of the mandrel of a helical groove into one end of which thewire is fed. The rotatable sleeve closely engages the outer surface ofthe mandrel so that the spring wire is confined within the groove. Thegroove is cut with the helical pitch which it is desired that thefinished spring shall assume and suflicient turns are made about themandrel to remove any tendency for the spring to assume a differentpitch when released from the mandrel.

Another feature of the invention resides in the fact that the mandrel ismade larger in" diameter at one end than at the other. The spring wireis fed to the larger end and thus assumes the final diameter in agradual manner. The initial bending effect of the sleeve upon the wireis thus distributed over several turns so that a coil may be formedhaving a smaller diameter than could be formed if the initial bendingeffect were confined to a single turn.

Another feature of the invention resides in the fact that the rate ofrotation of the rotatable sleeve is such that the internal surface ofsaid sleeve in contact with the wire assumes a linear velocity greaterthan the rate of advance of the wire. Thus the frictional effect of thesleeve upon the wire is much greater than would be the case if the saidvelocities were equal.

Other features of the invention will be understood from the accompanyingdrawing and the following description and claims:

Figure 1 is an end elevational view of the device with parts cut away toshow other parts in detail. Herein the device is shown as an attachmentto the frame of another machine, such as a bed spring weaving machine,but the scope of the invention is not to be limited by such showing.Figure 2 is a horizontal sectional view taken on the line 22 ofFigure 1. Figure 3 is a vertical sectional view taken substantially onthe line 33 of Figure 2. Figure 4 is a side view of a preferred form ofthe mandrel used.

The device is herein shown carried by a housing 10 which forms a part ofthe frame of a machine such as a bed spring weaving machine. The saidhousing is fitted with a cap casting 11 fastened thereto by cap screws12. A cylindrical member 13 is clamped in a suitable opening between thehousing 10 and the cap 11 and a ball bearing 14 is similarly clampedopposite thereto. A similar ball bearing 15 is retained by a set screw16 in the cylindrical member 13. The said ball bearings rotatablysupport a sleeve 1'7 carrying an internal sleeve 18 fastened therein bymeans of a screw 19. A mandrel is formed with a shank 20 closely fittingwithin the sleeve 18 and a portion 22 extending into the cylindricalmember 13 and locked therein by means of a set screw 23. The shankportion 20 of the mandrel is formed as best shown in Figure 2 with ahelical groove 24 cut in its outer surface. This portion of the mandrelis larger at its left end than at its right end and tapers downwardlyfrom the left over the length of several turns of the helical groove. Acollar 21 is fitted within a recess in the cylindrical member 13 and islocked therein by means of a set screw 21a. .A hardened guide bushing 25extends through a suitable hole in the cylindrical member 13 and theinner end thereof enters the collar 21. The guide bushing 25 is formedwith a central passage 20 which is continued by a passage 27 in thecollar 21. The passage 27 communicates with the end of the helicalgroove 24. A pair of feed rolls 28- are suitably mounted in position toguide a wire 29 into the guide bushing 25. The said feedrolls are powerdriven by a suitable connection with the machine to which the device-isattached and serve to regulate the rate of feed of the wire 28.

The sleeve 17 carries a spiral gear 30 fastened thereto by means of akey 31. Thegear 30 meshes with a spiral gear 32 carried upon a shaft 33,one end of which is supportedv by a ball bearing 34 carried by the cap11. The opposite end of the shaft 33 is suitably supported within themachine to which the device is attached and the said shaft is rotated byrotating portions of said machine.

In the operation of the device, the spring wire is fed between the rolls28, through the guide passages 26 and 27 and into the helical groove 24.The sleeves 17 and 18 are rotated by means of shaft 33 and gears 30 and32 in the same direction as the advance of the wire through the helicalgroove 24. The speeds of rotation of the feed wheels 28 and the sleeve18 are such that the internal surface of the sleeve 18 rotates with agreater linear speed than the linear speed of advance of the wire. It isto be noted that while the frictional effect of the-feed wheels 28 issuflicient to regulate the rate of movement of the wire, it is notordinarily sufficient in itself to advance the wire through the helicalgroove 24. The balance of the force necessary to advance the wire issupplied by the friction of the sleeve 18 because of the excess in thespeed of said sleeve. The frictional effect of the said sleeve on thewire winds the same firmly about the mandrel 20 within the groove 24.The length of the mandrel is so chosen that when the wire reaches theend thereof, all tendency for the wire to assume a coil diameter orpitch other than that of the helical groove 24 has been overcome. Thehelical spring so formed is, therefore, so accurate in pitch anddiameter that it may be fed directly into engagement with the springlast woven into the bed spring without manual or mechanical guidance.

It is also to be noticed that the construction of the device is suchthat mandrels of different sizes and pitches may be easily interchanged.When a mandrel of a different diameter is to be used, it is onlynecessary to substitute a corresponding internal sleeve 18 withoutdisturbing external sleeve 17. When left hand coils are to be wound, thecylindrical member 13 is replaced by one having the guide bushing 25leading to the upper edge of the mandrel shank instead of the lower, asshown herein. A mandrel having a left hand helix cut therein is thenused and the direction of rotation of the sleeve 18 is reversed bysuitable reverse mechanism or by replacing the gears 30 and 32 with anoppositely rotating pair of similar gears.

While a preferred form of the invention has been specifically disclosedherein, variations from the details thereof may be made withoutdeparting from the scope of the invention as defined by the followingclaims.

The invention claimed is:

l. A spring coiling device including a mandrel having a. larger diameterat one end than at the other, a rotatable sleeve surrounding saidmandrel, means for feeding spring wire between said mandrel and sleeveat the large end of said mandrel, and means for rotating said sleeve towind said wire about said mandrel.

2. A spring coiling device including a mandrel having a larger diameterat one end than at the other, a rotatable sleeve surrounding saidmandrel, means for feeding spring wire between said mandrel and sleeveat the large end of said mandrel, and means for rotating said sleeve ata speed which imparts to its internal surface a linear speed at least asgreat as the rate of feeding of said spring wire to wind said wire aboutsaid mandrel.

3. A spring coiling device including a mandrel having a larger diameterat one end than the other and having a helical groove. in its outersurface, a rotatable sleeve surrounding said mandrel and closely fittingthe same, means for feeding spring wire into the end of said helicalgroove at the large end of said mandrel, and means for rotating saidsleeve to wind saidwire about said mandrel.

4. A spring-coiling device including a mandrel having a larger diameterat one end than the other and having a helical groove in its outersurface, a rotatable sleeve surrounding said mandrel and closely fittingthe same, means for feeding spring wire into the end of said helicalgroove at the large end of said mandrel, and means for rotating saidsleeve at a speed which imparts to its internal surface a linear speedat least as great as'the rate of feeding of said spring wire to windsaid wire about said mandrel in said groove.

5. A spring coiling device including a mandrel having a larger diameterat one end than at the other, a rotatable sleeve surrounding saidmandrel, means for guiding spring wire between said mandrel and sleeveat the large end of said mandrel, and means for rotating said sleeve towind said wire about said mandrel.

6. A spring coiling device including a mandrel having a larger diameterat one end than the other and having a helical groove in its outersurface, a rotatable sleeve surrounding said mandrel and closely fittingthe same, means for guiding spring wire into the end of said helicalgroove at the large end of said mandrel, and means for rotating saidsleeve to wind said wire about said mandrel.

WHLIAM H. MOON.

